大涡模拟壁湍流雷诺剪切应力



  • 最近验证算例,LES模拟壁面湍流,与文献结果对比,雷诺应力偏离较大;
    采用边界层网格,第一层网格尺寸满足y+=1,入口出口cyclicAMI周期边界条件,因为是不可压缩,所以fvoption直接给出的是Ubar,大概算了80个周期后,做时均,平均速度与文献结果差不多,但关于速度脉动的湍动能和雷诺应力完全不一致,这个问题一直也没有解决,求教高手解答;
    注:关于雷诺剪切应力我是通过uprime2mean_xy+turbulencefieldsR_xy得到的,模拟输出的turbulencefieldsR相比uprime2mean来说很小;



    1. 可以出个图看看差别有多大

    2. LES那面Van Driest dampling用的比较多,从文献来看可以大大改善壁面附近的预测



  • @东岳 老师,目前在试算,所以我用的是一套二维网格,亚格子模型为WALE

    simulationType LES;
    
    LES
    {
        LESModel        WALE;
    
        turbulence      on;
    
        printCoeffs     on;
    
        delta           cubeRootVol ;
    
        cubeRootVolCoeffs
        {
            deltaCoeff      1;
        }
    
        PrandtlCoeffs
        {
            delta           cubeRootVol;
            cubeRootVolCoeffs
            {
                deltaCoeff      1;
            }
    
            smoothCoeffs
            {
                delta           cubeRootVol;
                cubeRootVolCoeffs
                {
                    deltaCoeff      1;
                }
    
                maxDeltaRatio   1.1;
            }
    
            Cdelta          0.158;
        }
    
        vanDriestCoeffs
        {
            delta           cubeRootVol;
            cubeRootVolCoeffs
            {
                deltaCoeff      1;
            }
    
            smoothCoeffs
            {
                delta           cubeRootVol;
                cubeRootVolCoeffs
                {
                    deltaCoeff      1;
                }
    
                maxDeltaRatio   1.1;
            }
    
            Aplus           26;
            Cdelta          0.158;
        }
    
        smoothCoeffs
        {
            delta           cubeRootVol;
            cubeRootVolCoeffs
            {
                deltaCoeff      1;
            }
    
            maxDeltaRatio   1.1;
        }
    }
    

    您说的van driest damping是vanDriestCoeffs里的设置吗?
    1562635936(1).jpg
    上面的图是平均速度,实验数据为黑线,下方的正弦曲线是底部边界;5-30s我开始认为湍流没有完全发展,所以一直算到200s,又对100-200s取时均,定性上看,两个时间段的平均速度变化差不多;
    雷诺应力的图被我删掉了,有关于湍动能的结果,实验数据为黑线,这个就完全不一致,而且不同时间段的湍动能时均值也不一致;
    1562635976(1).jpg
    以下是我的设置:

    FoamFile
    {
        version     2.0;
        format      ascii;
        class       volScalarField;
        object      nut;
    }
    // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
    
    dimensions      [0 2 -1 0 0 0 0];
    
    internalField   uniform 0;
    
    boundaryField
    {
        INLET
        {
            type            cyclicAMI;
        }
    
        OUTLET
        {
            type            cyclicAMI;
        }
    
        BOTTOMWALL
        {
            type            nutUSpaldingWallFunction;
            value           uniform 0;
        }
    
        ATMOSPHERE
        {
            type            nutUSpaldingWallFunction;
            value           uniform 0;
          
        }
        
        frontAndBackPlanes
        {
            type            empty;
        }
    
       
    }
    
    FoamFile
    {
        version     2.0;
        format      ascii;
        class       volScalarField;
        object      p;
    }
    // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
    
    dimensions      [0 2 -2 0 0 0 0];
    
    internalField   uniform 0;
    
    boundaryField
    {
        INLET
        {
            type            cyclicAMI;
        }
    
        OUTLET
        {
            type            cyclicAMI;
        }
    
        BOTTOMWALL
        {
            type            zeroGradient;
        }
    
        ATMOSPHERE
        {
            type            zeroGradient;
            //p0              uniform 0;
        }
        
        frontAndBackPlanes
        {
            type            empty;
        }
    
     
    }
    
    FoamFile
    {
        version     2.0;
        format      ascii;
        class       volVectorField;
        object      U;
    }
    // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
    
    dimensions      [0 1 -1 0 0 0 0];
    
    internalField   uniform (0 0 0);
    
    boundaryField
    {
        INLET
        {
            type                cyclicAMI;
        }
    
        OUTLET
        {
            type                cyclicAMI;
        }
    
        ATMOSPHERE
        {
            type                noSlip;
            //value               uniform (0 0 0);
        }
    
        BOTTOMWALL
        {
            type                noSlip;
            
        }
    
        frontAndBackPlanes
        {
            type            empty;
        }
    }
    
    FoamFile
    {
        version     2.0;
        format      ascii;
        class       dictionary;
        location    "constant";
        object      fvOptions;
    }
    // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
    
    momentumSource
    {
        type            meanVelocityForce;
    
        selectionMode   all;
    
        fields          (U);
        Ubar            (0.08 0 0);
    }
    
    FoamFile
    {
        version     2.0;
        format      ascii;
        class       dictionary;
        location    "system";
        object      fvSchemes;
    }
    // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
    
    ddtSchemes
    {
        default         Euler;
    }
    
    gradSchemes
    {
        default         Gauss linear;
    }
    
    divSchemes
    {
        default         none;
        div(phi,U)      bounded Gauss linearUpwind grad(U);
        div(phi,k)      bounded Gauss limitedLinear 1;
        div(phi,epsilon) bounded Gauss limitedLinear 1;
        div(phi,omega)  bounded Gauss limitedLinear 1;
        div(phi,v2)     bounded Gauss limitedLinear 1;
        div((nuEff*dev2(T(grad(U))))) Gauss linear;
        div(nonlinearStress) Gauss linear;
    }
    
    laplacianSchemes
    {
        default         Gauss linear corrected;
    }
    
    interpolationSchemes
    {
        default         linear;
    }
    
    snGradSchemes
    {
        default         corrected;
    }
    
    wallDist
    {
        method meshWave;
    }
    
    FoamFile
    {
        version     2.0;
        format      ascii;
        class       dictionary;
        location    "system";
        object      fvSolution;
    }
    // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
    
    solvers
    {
        p
        {
            solver          PCG;
            preconditioner  DIC;
            tolerance       1e-06
            relTol          0.05;
        }
    
        pFinal
        {
            $p;
            relTol          0;
        };
    
        "(U|k|B|nuTilda)"
        {
            solver          smoothSolver;
            smoother        GaussSeidel;
            tolerance       1e-05;
            relTol          0;
        }
    }
    
    PISO
    {
        nCorrectors     2;
        nNonOrthogonalCorrectors 0;
        pRefCell        0;
        pRefValue       0;
    }
    

    希望得到老师的回复,谢谢。



  • @ewz 把你的divSchemes里面的bounded去掉,然后时间精度换backward试试。还有就是nut的边界条件nutUSpaldingWallFunction,这个可以换别的试试,具体哪个更好也说不清。

    另外,你模拟的是什么?挺有意思的,要发SCI么,可以考虑下 http://www.cfd-china.com/topic/1716/cfd验证算例支持计划

    黑线是实验数据,红线是什么?

    vanDriest这样用:

    simulationType LES;
    
    LES
    {
        LESModel        WALE;
    
        turbulence      on;
    
        printCoeffs     on;
    
        delta           vanDriest;//
    
        cubeRootVolCoeffs
        {
            deltaCoeff      1;
        }
    
        PrandtlCoeffs
        {
            delta           cubeRootVol;
            cubeRootVolCoeffs
            {
                deltaCoeff      1;
            }
    
            smoothCoeffs
            {
                delta           cubeRootVol;
                cubeRootVolCoeffs
                {
                    deltaCoeff      1;
                }
    
                maxDeltaRatio   1.1;
            }
    
            Cdelta          0.158;
        }
    
        vanDriestCoeffs
        {
            delta           cubeRootVol;
            cubeRootVolCoeffs
            {
                deltaCoeff      1;
            }
    
            smoothCoeffs
            {
                delta           cubeRootVol;
                cubeRootVolCoeffs
                {
                    deltaCoeff      1;
                }
    
                maxDeltaRatio   1.1;
            }
    
            Aplus           26;
            Cdelta          0.158;
        }
    
        smoothCoeffs
        {
            delta           cubeRootVol;
            cubeRootVolCoeffs
            {
                deltaCoeff      1;
            }
    
            maxDeltaRatio   1.1;
        }
    }
    


  • @东岳 好的,谢谢老师!我调试参数再算一下;
    我模拟的是wave surface壁面湍流,因为目前是验证LES的阶段,就找了一篇关于实验的文献;
    红线数据是三维计算域的实验结果;


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